In general, in a cooking apparatus using microwaves, when an operation button is pressed after food is put into a cavity and then the cavity is sealed, voltage is applied to a high-voltage transformer, the commercial voltage applied to the high-voltage transformer is boosted to high-voltage power, the power is applied to a magnetron to generate microwaves and the microwaves generated by the magnetron are transmitted to the cavity through a waveguide, etc.
Here, the cooking apparatus using microwaves heats the food using frictional force generated by vibration of molecules of the food 2,450,000,000 times per second due to irradiation of the microwaves generated by the magnetron onto the food.
Such a cooking apparatus using microwaves has advantages, such as ease of temperature control, cooking time saving, convenience in operation, etc., and thus has been broadly distributed in many households.
However, if food is cooked using microwaves, the food is not uniformly heated due to surface variation of the food and a partial temperature difference of the food may occur. Further, temperature variation during cooking may occur according to kinds of food accommodated in the cooking apparatus.